1. Field of the Invention
The present invention generally relates to an image processing method, and more particularly, to a carry manner of pixels of a pixel block upon a reduction of bit numbers of the pixels.
2. Description of Related Art
Among the current image processing technologies, dither technology is one for improving a grey level resolution. For example, when a 6-bit driving chip is used to display an 8-bit image, a typical solution is to convert the 8-bit image into a 6-bit image. In order to reduce the loss of information during the conversion from the 8-bit image to the 6-bit image, the pixels are usually carried respectively during the conversion. Details are to be illustrated herebelow facilitated with drawings.
FIG. 1 schematically illustrates a conventional carry manner of a 2×2 pixel block. FIG. 2 is a schematic diagram illustrating a conventional conversion from an 8-bit pixel block to a 6-bit pixel block. Referring to FIGS. 1 and 2 together, for example, a pixel resolution of a display assumed to be 1920×1200 is provided for viewing the 2×2 pixel block. Here, we suppose that the display is going to convert the 8-bit pixel block 10 into a 6-bit pixel block, in which the 8-bit pixel block 10 is constituted by pixels (1, 1), (1, 2), (2, 1), and (2, 2).
First, the display detects a least significant bit (LSB), and the LSB is detected to be 10. Then, as shown in FIG. 1, a carry manner of subsequent consecutive frames is determined according to the LSB. Accordingly, in a first frame, the 8-bit pixel block 10 is converted to a 6-bit pixel block 11, in which the pixels (1, 1) and (2, 2) are carried, and pixels (1, 2) and (2, 1) are remained non-carried. In a second frame, the 8-bit pixel block 10 is converted to a 6-bit pixel block 12, in which the pixels (1, 2) and (2, 1) are carried, and pixels (1, 1) and (2, 2) are remained non-carried. In a third frame, the 8-bit pixel block 10 is converted to a 6-bit pixel block 13, in which the pixels (1, 1) and (2, 2) are carried, and pixels (1, 2) and (2, 1) are remained non-carried. In a fourth frame, the 8-bit pixel block 10 is converted to a 6-bit pixel block 14, in which the pixels (1, 2) and (2, 1) are carried, and pixels (1, 1) and (2, 2) are remained non-carried.
It should be noted that displaying performance of the display varies in accordance with different manners employed for carrying the pixel blocks. The carry manner as shown in FIG. 1 usually causes image flickering which leads to an unsatisfactory displaying performance. As such, a further conventional technology provides another carry manner as discussed below.
FIG. 3 schematically illustrates a carry manner of a 4×4 pixel block. The carry manner of FIG. 3, to some degree, improves the flickering image. However, as shown in FIG. 3, when the LSB value is 01 or 11, the carry manners of each pixel of a pixel block in two consecutive frames are symmetric one to another. Such symmetric carry manners often cause transverse striations and/or vertical striations, which seriously destroys the displaying performance of the display.